Advantages of virtual microscopes include the fact that they're a great learning tool, and they require no maintenance. Disadvantages include the fact that the samples are not able to be rescanned, and the ability to manipulate images is limited.

There is no proportional or inversely proportional relationship between dot pitch and refresh rate.

The higher the dot pitch, the tighter packed pixels are, meaning more rows and more columns in the same space. Typically higher video resolutions can be achieved.

The higher the refresh rate, the faster all rows are rescanned. Measured in Hertz, or the number of complete scans per second.

This varies slightly from place to place.

The pelvic CT may require you to drink an oral preparation before the test and it may require an injection into a vein in your arm. This depends on what the doctor wants to see on your test. Your doctor will make an order telling the CT technologist what he wants or he may already have routine orders in place for what he wants for a certain test. The patient lays on the CT scan table for usually less than 10 minutes and newer machines may be less than 5 minutes. There are a few rare CT scans that may take longer or might require you to get rescanned after a certain time length. All of the above should be altered to what will give you the best scan.

The yolk sac first becomes visible at 5 weeks. By the end of the week it should be visible. If it is not, there is always the possibility that conception occurred later than the dates suggest, and so the baby would not yet be 5 weeks old.